With the rapid development of information technology, network resources show explosive growth. A network resource portfolio may produce more beneficial results. For example, in the field of information pushing, the portfolio of a user's location resources and demand resources can push, to the user, more information in line with user's needs, which helps to improve the accuracy of information pushing. As another example, in the field of investment banking, buying a portfolio of a variety of financial products can reduce investment risk, and helps to improve investment income.
In different periods or different scenarios, the beneficial effects a network resource portfolio can bring may be different, which means that the network resource portfolio are not static, needs constantly adjustment of the network resource portfolio. However, how to determine whether it is necessary to adjust the network resource portfolio is the first problem to solve.